My 2001 Jimmy makes a loud almost sounds like a helicopter noise when in 2 wheel drive when i put in 4 hi the noise goes away however it makes a loud banging noise after i take a turn i have recently replaced the wheel bearing and ball joint. When in 2 wheel drive front right does not release from 4x4

 

If you have the 3 button 4WD dash switch, this applies to your vehicle. If you have the 4 button dash switch, (Auto 4WD) it does not apply.

Under the battery tray is a vacuum actuator. When vacuum is applied to it, it pulls a cable that operates a shift fork to engage the right front axle with the differential. There is a vacuum switch on the transfer case that applies vacuum to the actuator when you select 4WD. If the vacuum switch leaks internally, it can partially apply vacuum to the actuator causing the "helicopter" noise. What you are hearing is two gears trying to mesh together. You can unplug the vacuum line from the actuator to test this theory. If the noise stops, leaky vacuum switch is the problem. Approximately $20 part and 20 minutes to replace it.

 

Ty will try that